THE PREPARATION AND EVALUATION OF ULTRAMICRO-SENSOR MODIFIED POLYMETHACRYLOYLACETC

采用固定化聚甲基丙烯丙酮（PMAA）制备了一种用于金属离子测量的多孔超微电极。多孔碳材料被填充在铂微电极的尖端，顶部有一个空腔。将多孔超微电极浸在含PMAA和邻苯二甲酸二乙己基酯的四氢呋喃涂层溶液中，室温下干燥过夜。在最佳条件下考察了金属离子浓度与氧化峰电流的关系。在0.01 mM ~ 1mm铁离子范围内呈线性关系。标定曲线为方程Y = 2.42 2x -0.414，其中Y为氧化峰电流（nA）， X为铁离子浓度（mm），回归系数为0.999。利用该电极还可以测定Cu（II）、Pb（II）和Mo(V)离子。由于Cu（II）和Pb（II）离子的最佳测定条件相似，因此只能同时测定Cu（II）和Pb（II）离子。电极保存在pH 6.0的磷酸盐缓冲液中，室温保存。用改良电极测定的分析值在至少3个月内保持不变

A porous ultramicro-electrode with immobilized polymethacryloylacetone(PMAA) was developed for measuring metal ions. A porous carbon material was packed into the tip of the platinum micro-electrode with a cavity at the top. The porous ultramicro-electrode was dipped in the coating tetrahydrofuran solution with PMAA and di-2-ethylhexyl phthalate and dried overnight at room temperature. The relationship between the metal ion concentrations and oxidation peak current were examined under the optimum conditions. A linear relationship was obtained in the range of 0.01 mM - 1 mM iron ion. The calibration curve could be represented by the equation Y = 2.42X -0.414, where Y is the oxidation peak current in nA and X is the iron ion concentration in mM.The regression coefficient was 0.999. By use of this electrode, Cu(II), Pb(II), and Mo(V) ions could also be deternined. The simultaneous determination was possible only for the mixture of Cu(II) and Pb(II) ions because the optimal conditions for these ions were similar to each other. The electrode was stored in a pH 6.0 phosphate buffer solution at room temperature. Analytical values determined with the modified electrode was constant for at least 3 months